Many medical devices used in intensive care units of hospitals provide acoustic (audible) alarms, if specific conditions or events occur. The medical device or devices are typically arranged near to a patient's bed and are provided for monitoring one or more physiological characteristics of a patient, such as heart rate, blood pressure, breathing rate, blood oxygen levels, etc, and/or for providing some treatment to a patient, such as controlling the administration of an intravenous drug, assisting the patient's breathing, etc. The specific conditions that lead to alarms being triggered can refer to, for example, abnormal values of the physiological characteristics of the patient or specific operating states or error states of the device.
The alarms issued by these devices are primarily for the attention of the healthcare staff in the hospital and serve to acoustically alert staff members to direct their attention to the device and take any appropriate or required action. Although the alarm sound level for a particular medical device may be able to be set by the end users (the healthcare staff) to specific levels, these levels will typically stay fixed after being set during installation, which means that alarm sounds are played with a fixed absolute sound power level. This level will have been set sufficiently high to hopefully guarantee that healthcare staff will be alerted despite the background noise in the environment in which the medical device is being used potentially being quite high (for example if many staff members are speaking simultaneously and/or if there are lots of noisy medical devices being used, which may themselves be issuing alarms). However, this means that the alarm can be much louder than necessary when there are low background noise levels, such as at night. Due to their function of raising auditory attention, these sounds are also well-suited to arouse patients during sleep, leading to sleep fragmentation, anxiousness about the meaning of the sounds, or just annoyance if the alarms are not acted on for a long period.
As the number of individual acoustic alarms being generated in such an environment (particularly in an intensive care unit) at any one time can be very high, these sounds can contribute in many cases to a highly stressful situation for the healthcare staff as well as for any nearby patients. It has been found that such stress overload can lead to staff suffering from “alarm fatigue” where a staff member is no longer able to react appropriately to the alarms, and in some cases can lead to staff members ignoring the alarms altogether.
Therefore, there is a need for an apparatus and method of operating the same that generates a specific or predetermined sound, for example an alarm, which reduces the potential negative impacts of alarm sounds on patients and healthcare staff outlined above, while ensuring that the alarm sounds remain highly audible without being unnecessarily loud.